Medical research has shown that low birthweight and premature births, particularly those of low-income families, are at higher risk for later intellectual or behavioral problems. This proposed research will attempt to verify a procedure for identifying within selected health areas clusters of adverse birth outcomes, with the ultimate goal of providing a timely prenatal outreach program for current high-risk gravidae in the same areas. The proposed work is based upon a preliminary study of all births and fetal deaths occurring in 14 New York City health areas in a single year. It was found that adverse outcomes of pregnancy apparently tend to cluster within certain blocks rather than occur homogeneously throughout an area. In this first study 50% of the adverse outcomes were found in 15 percent of the blocks plus a few additional buildings. We plan to verify this preliminary finding by analyzing similar data over a three-year time period and by applying a more rigorous statistical measure of clustering. If the clustering pattern can be demonstrated over time, it will provide prenatal outreach workers with essential data for contacting the subgroup of the population most in need of, and least likely to be receiving, adequate prenatal care.